Relative risks of late and moderately preterm (LMPT) birth for lifestyle factors from multivariable model, before and after including mother's age, ethnicity, body mass index (BMI) and educational level
| Indicator | Risk of late and moderate preterm birth | |||||
|---|---|---|---|---|---|---|
| Model including lifestyle factors | Model including lifestyle factors adjusted for socio-demographic factors | |||||
| Relative risk | 95% CI | p Value | Relative risk | 95% CI | p Value | |
| Lifestyle factors | ||||||
| Use of recreational drugs during pregnancy | ||||||
| No | 1 | – | 0.486 | 1 | – | 0.495 |
| Yes | 1.27 | 0.65 to 2.51 | 1.27 | 0.64 to 2.50 | ||
| Smoking status | ||||||
| Non-smoker | 1 | – | 0.027 | 1 | – | 0.082 |
| Gave up before pregnancy | 0.86 | 0.67 to 1.09 | 0.93 | 0.72 to 1.20 | ||
| Gave up in first trimester | 1.07 | 0.73 to 1.56 | 1.12 | 0.76 to 1.66 | ||
| Smoker during pregnancy | 1.35 | 1.05 to 1.72 | 1.38 | 1.04 to 1.84 | ||
| Alcohol use | ||||||
| Non-drinker | 1 | – | 0.205 | 1 | – | 0.918 |
| Gave up before pregnancy | 0.83 | 0.66 to 1.04 | 1.02 | 0.78 to 1.34 | ||
| Gave up in first trimester | 0.78 | 0.61 to 0.99 | 0.98 | 0.73 to 1.31 | ||
| Drank during pregnancy | 0.86 | 0.66 to 1.13 | 1.08 | 0.79 to 1.48 | ||
| Daily consumption of five fruit and vegetables | ||||||
| At least once a week | 1 | – | 0.022 | 1 | – | 0.027 |
| Never | 1.31 | 1.04 to 1.64 | 1.31 | 1.03 to 1.66 | ||
| Mediterranean diet factors | ||||||
| ≥1 | 1 | – | 0.052 | 1 | – | 0.036 |
| None | 1.71 | 1.00 to 2.92 | 1.81 | 1.04 to 3.14 | ||
| Socio-demographic factors | ||||||
| Mother's age (years) | ||||||
| <20 | 1 | – | 0.585 | |||
| 20–29 | 1.31 | 0.86 to 1.99 | ||||
| 30–39 | 1.37 | 0.88 to 2.13 | ||||
| 40+ | 1.32 | 0.71 to 2.45 | ||||
| Mother's educational level | ||||||
| Degree level and above | 1 | – | 0.052 | |||
| University-access level | 1.29 | 1.00 to 1.66 | ||||
| Upper secondary qualification | 1.36 | 1.06 to 1.76 | ||||
| No formal/lower secondary qualification | 1.42 | 1.06 to 1.89 | ||||
| Mother's ethnicity | ||||||
| White | 1 | – | 0.025 | |||
| Mixed | 1.70 | 0.97 to 2.99 | ||||
| Asian or Asian British | 1.54 | 1.13 to 2.11 | ||||
| Black or Black British | 1.36 | 0.89 to 2.08 | ||||
| Chinese or other ethnic group | 1.99 | 0.87 to 4.55 | ||||
| Mother's BMI | ||||||
| 20.0–24.9 | 1 | – | 0.001 | |||
| <20 | 1.12 | 0.75 to 1.67 | ||||
| 25.0–29.9 | 0.80 | 0.64 to 1.00 | ||||
| ≥30 | 0.58 | 0.45 to 0.76 | ||||
| No pre-pregnancy weight recorded | 1.07 | 0.57 to 2.02 | ||||